Lifting grab for industrial trucks



Feb. 26, 1952 J, MCDONALD 2,586,843

LIFTING GRAB FOR INDUSTRIAL TRUCKS Filed Aug. 5, 1947 2 SHEETSSHEET l ATTORNEY Feb. 26, 1952 J MCDONALD LIP-TING GRAB FOR INDUSTRIAL TRUCKS Filed Aug. 5, 1947 2 SHEETS-SHEET 2 J v INVENT w J/womzd Patented Feb. 26, 1952 sm te-s ear-stir oseice LIFTIN G 'GR-ABTOR INDUSTRIAL TRUCKS; Hiram-J. McDonald, J eflersonville,:Ind.-

Application'Augustfi, 1947, Serial No. 766,433

4 Cla'imszx (Cl. 214-66) (Gi anted'under the, act of March a; 1883; as

amended"Apri130;: 1928; 3'70 '0. vGr. 757) The invention :described. herein, patented, may; be manufactured and. used by or for. ,the.

Government for governmental purposes, with:

out the'payment do me of any royalty thereon This invention relates to loading apparatus; and is particularly concerned with a 1 mechanism) for grippingrlan article-to be lifted and transported toa pointof'deposit; V

Morespecifiallyit is. an object of the invention to provideea n attachmentpfor industrial: trucks, such as fork-lift trucks, adapted to grip articles -whichsare to be lifted and transported from-.one place to another as in. the handling of goodsfor storage, shipment; etc.

A further object or the invention re sides m tts provision-ct a gripping mechanism; for indus';v trialv trucks which :will operate automatically to grasp .-the articlemto :be-lifted thus. eliminating.

the need of a special attendant for that purpose.

Other objects ancl'advantages-of the invention. will be apparent; fiom the following description when takenin 'connection with the accompanying: drawings, in which,v

Figureul -is a fragmentaryperspective view of the :forward-wportion 'of'an industrial truk with the novel attachment installed thereon and about to engage fan-article tobe lifted;

Figure 2 isa fragmentary elevational view. of the attachment in gripping position upon .a. box;

Figure 3 is a plane View of the apparatus; and

Figure 4- is an enlarged detailed perspective view showing the spring mounting and related parts.

In detail; the numeral l indicates a'fork lift truck provided with a mast 2 pivoted to the body of the :trucktand adapted tobe tilted forwardly or backwardly as desired. Slidably mountedxon the forward'portion of the mastis a carriage 3 adaptedito be raised and lowered. for the-purpose o'f liftingmerchandise when it. is: to be transported'and deposited in a new location.

The parts just. referred to are well known in v the art and form no' part of' the'present invention except insofar as they are combined with the'novel f'eaturesto be-described. Fixeditothe' carriage 3 and extending forwardly and horizontally therefrom is a boom 4 for supporting lazy tongs for gripping articles to be transported by the truck.

Swiveled to the forward end of boom 4, as by means of bolt and nut 5 is a crossbeam 6 to the ends of which the lazy tongs are pivotally connected. In the present instance, the lazy tongs comprise a set of two which are pivotally connected to the respective ends of the bar 6 and have their. corresponding elementsrig-idly connectedso as to act in unison. The pivot for each of thelazy tong iin the respective ends of the bar. B'isindicated by the numeral I and the links for. this part of the lazy tongs areindicated by the numeral 8. Pivotally connected-to the opposite ends of thelinks 8 as indicated by numeral 9 are the vmain levers it of. the lazy tongs and.

in the present illustration, grippers H of V- shaped cross-section are rigidly connected to the.

free ends of theleversilfl. Thesegrippersmay beprcvided with linings l2 of. suitable fabric.

such as brake lining material orthe like when the apparatus is. to be used for handling articles which might be damaged by the bare metal of the grippers. In I the. present instance, the boxes A, which are shippingv crates=for caskets. have. their longitudinal upper edges provided with ribs.

B. whichare readily adapted to receive the .channeled grippers ll. Itis to beunderstood'howe'verithat. the invention. is not so limited and that various other types. of grippingmeans may be substituted for ,the elements I I;

In addition tothe grippers. l I :which connect the free ends ofthelevers 10, the bars- I3 rigidly connect .thesel-levers so as to .provide a sturdy and unitaryconstructiong Moreover,- these bars i3..are. preferablyprovided with guide loops l4. whichserve-to slidably engage the free ends of a leaf spring ldwhich maybe secured at its midpcrtion to. the swivel. bolt 5-and has its free ends.

disposed'beneaththe two crossibars. l3 for the pnrposeof normally maintaininglthengrippers H in their open position.

It will beflunderstoodqthatthe lateral pressure applied by, the grippers in gripping a heavy articl-ewill bevery substantial and inthe case-of boxes and similar articles might cause considerable. damageif not=modified to some extent. In-

the present construction therefore asbar l6 extends across the space between the i-gripperslL and has its ends connected thereto by the p-in and slot. connections- H,- thereby PIOVldlngwfOI' adeq uate relative movement between-1 the grippers 1 but limiting their; inward movement so asto the rear gripper into alignment with the adjacent rib B on the upper edge of the box. The truck is then moved forwardly to bring the rear gripper into gripping engagement with the rear rib B and the mast 2 is tilted forwardly to vertical position thereby bringing the forward gripper i i into the horizontal plane of the rear gripper i I and, of course, into the plane of the other rib B. Power may then be applied to the carriage 3 to elevate the same and in this movement the lazy tongs will operate to bring the forward gripper into tight engagement with the adjacent rib B and thereby tightly grip the box between the grippers in the usual and well known operation of tongs of this general type. after the truck may be operated to carry the article A to its point of deposit and the latter will be lowered to the floor or other place of storage and in this position the grippers II will automatically release the article through pressure of the spring IS on the' cross bars l3, and set the grippers in position for a succeeding operation as soon as the mast 2 is tilted rearwardly to set the rear gripper in a horizontal plane slightly below the plane of the forward gripper.

From the foregoing description taken into connection with the accompanying drawings it will be apparent to those skilled in the art that I have devised an attachment for lift-trucks which is of relatively simple construction and yet which may be operated through the maneuvering of the truck itself to cause the grippers to automatically engage and disengage an article to be handled, thereby eliminating the need for one or more workmen in otherwise attaching the article to the lifting means, and that by reason of the swivel connection between gripping device and the horizontal beam, elongated articles such as the crate A may be readily rotated through an angle of 90 or other desired angle should it be necessary to transport the article through narrow passages or doorways.

While the apparatus illustrated herein has been described in some detail, it is to be understood that various types of grippers may be substitutecl for the inwardly opening channel members and that various other changes may be made without in any way departing from the spirit of the invention and it is intended that all such changes be included within the scope of the appended claims.

I claim:

1. In combination with a fork-lift truck havmg an upright mast pivoted for swinging movement forwardly and backwardly, a carriage mounted for vertical movement on the mast. 9.

Thereboom projecting from the carriage, a pair of lazy tongs arranged in parallel relation, cross-rods rigidly connecting the corresponding levers of said pair of lazy tongs, inwardly directed channel members connecting the corresponding free ends of the pair of lazy tongs, a spring for normally maintaining said tongs in open position, and. means for pivotally connecting said tongs to the boom.

2. In combination with a fork-lift truck having an upright mast pivoted for swinging movement forwardly and backwardly, a carriage mounted for vertical movement on the mast, a boom projecting from the carriage, lazy tongs, means for pivoting the lazy tongs on said boom, gripping means on the free ends of the tongs, a rigid bar spanning the space between the free ends of the tongs, and a pin and slot connection between each end of the bar and the adjacent free end of the tongs.

3. In combination with a fork-lift truck having an upright mast pivoted for swinging movement forwardly and backwardly, a carriage mounted for vertical movement on the mast, a boom projecting from the carriage, lazy tongs, means for pivoting the lazy tongs on said boom, gripping means on the free ends of the tongs, and a leaf spring fixed at its mid-portion to the suspending means and having its free ends in sliding engagement with the free ends of the tongs.

4. In combination with a fork-lift truck having an upright mast pivoted for swinging movement forwardly and backwardly and a movable carriage mounted on the mast for vertical movement, a boom projecting forwardly from the carriage, a pair of interconnected grippers pivotally connected to the boom, the operative face of one gripper directed forwardly and the operative face of the other gripper directed rearwardly, whereby when the rear gripper is engaged against an article to be lifted and the carriage is raised on the mast the grippers are caused to automatically grip the article.

. HIRAM J. MCDONALD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,518,560 Carroll Dec. 9, 1924 1,666,847 Cote Apr. 17, 1928 1,737,614 Peck Dec. 3, 1929 1,918,486 Onos July 18, 1933 2,323,810 Fontaine July 6, 1943 2,337,177 Breslav Dec. 21, 1943 2,387,744 Clapp Oct. 30, 1945 2,403,346 Deiters July 2, 1946 2,469,812 Breslav May 10, 1949 FOREIGN PATENTS Number Country Date 511,894 Great Britain Aug. 25, 1939 

